The present invention relates to a process for the preparation of beta-disubstituted monocarboxylic acids derived from acyclic, monocyclic, or bicyclic hydrocarbons.
These acids are useful as synthesis intermediates and as additives for oils and lubricants. Therefore, it is important to find a simple method of synthesis using an economic raw material. Thus, the interest of using petroleum fractions rich in isoparaffins for the synthesis of these acids is evident.
The synthesis of beta-disubstituted monocarboxylic acids by reacting a tertiary functional compound such as an alcohol, tertiary ether or halide, or an alkene with vinylidene chloride in a concentrated sulfuric acid medium and in the presence of BF.sub.3 followed by the hydrolysis of the reaction mixture by water is known (K. BOTT, H. HELLMAN, ANGEW. Chem 78 932 (1966)). ##STR1##
It is likewise known that adamantane, a polycyclic compound, reacts with vinylidene chloride according to the process described in the prior art. This very rigid structure has the peculiarity of reacting with vinylidene chloride to form a diacid, the 1,3, dicarboxymethyladamantane (U.S. Pat. No. 3,751,455). ##STR2##
This method makes use of a Lewis-acid type catalyst and specially of BF.sub.3, the use of which is complicated. An improvement on the preceding method has been proposed by A. NILSON and R. CARLSON (Acta. Chem. Scand. 1980 621) who have carried out the synthesis not in the presence of gaseous BF.sub.3 but of a soluble BF.sub.3 hydrate, but without eliminating the presence of BF.sub.3.
However, the main objection to this synthesis is that it cannot be applied to tertiary acyclic, monocyclic, or bicyclic hydrocarbons such as isoparaffins of petroleum origin.
In fact, the acyclic, monocyclic, or bicyclic tertiary hydrocarbons do not react with vinylidene chloride in a concentrated protonic acid medium even in the presence of a Lewis-acid type catalyst such as BF.sub.3.